The object of this invention concerns a method for repairing a warp break on weaving machines, together with the rethreading mechanisms used for this purpose.
As is well known, the warp threads on a weaving machine are led in turn through a warp stop motion device for detecting warp thread breaks, the harnesses and the reed. The warp stop motion device is made up of a series of drop wires; each drop wire is supported by one of the warp threads, so that if the thread breaks the drop wire falls and an electrical contact is made. The harnesses control the motion of the warp threads; they are made up of a series of heddles, each of which controls the motion of a single warp thread. The reed is used for beating up the weft threads in the normal way.
Clearly, given the large number of warp threads and consequently the same large number of drop wires and heddles, when a warp break occurs it is farily difficult to carry out a repair. The break first has to be located, then space has to be made in order to carry out the repair, and finally the repair has to be made. The first of these requirements is dealt with in the U.S. Pat. No. 4,791,967, filed Feb. 13, 1987, and assigned to the assignee of the present application and incorporated herein by reference. Concerning the second requirement, ie. to make space for access to the fallen drop wire and the area around it, use is made of a method and mechanism for twisting the drop wire. This method and the mechanism are described the U.S. patent application Ser. No. 072,003, filed July 10, 1987, and assigned to the assignee of the present application and incorporated herein by reference. The present invention concerns the third requirement, ie. the repair itself. In particular, the invention provides a method for repairing a warp break on weaving machines in such a way as to enable the subsequent rethreading to be carried out automatically, thus saving a great deal of the time and trouble.